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Friday, July 22, 2011

Robotic Single-Port Cholecystectomy Fails to Convince

I have resisted the urge to blog again about single-port [a.k.a. single-incision] laparoscopic cholecystectomy because I was afraid I would start swearing a lot, but I can contain myself no longer. The stakes have escalated with the appearance of a publish-ahead-of-print paper on robotic single-port laparoscopic cholecystectomy in Archives of Surgery.

One of the co-authors of this paper is the chief medical advisor for the company that makes the robotic surgery device and the other is a consultant. The paper is a pilot study of the feasibility of using the robot to perform single-port laparoscopic cholecystectomy. It attempts to retrospectively compare 10 patients done robotically to 10 patients who had standard, four-port laparoscopic cholecystectomies. Patients with acute cholecystitis were excluded from both groups.

One robotic case had to be converted first to a four-port laparoscopic approach and then to an open cholecystectomy. This patient was excluded from the analysis of the results, a flagrant violation of the “intention to treat” principle which is that all patients should remain in whatever group they originally were assigned to.

The robotic cases [minus, of course, the case that was converted] averaged 105 minutes in duration which was not significantly different than the four-port cases, which averaged 106 minutes. The authors concluded that this showed that the duration of robotic single-port laparoscopic cholecystectomy was equivalent to four-port laparoscopic cholecystectomy. Sounds great, right? Not really. This is a nice example of what is known in the statistics business as a “straw man.” A straw man is defined as establishing a control that is not representative of real life and then comparing the experimental group [favorably] to it. Most four-port laparoscopic cholecystectomies for non-inflamed gallbladders can be done in well under 60 minutes. For example, another recent paper comparing non-robotic single-port laparoscopic cholecystectomy to standard, four-port laparoscopic cholecystectomy noted mean case durations of 88 and 45 minutes respectively.

Of the nine analyzed robotic patients, two suffered urinary retention, one of whom had to be discharged with a catheter. This is a very rare complication of four-port surgery.

The authors state, “This approach [robotic single-port] appears to be safe, even in difficult cases with inflammation, and has a high degree of satisfaction with the patients.” It is difficult to see how they arrived at that conclusion since patients with inflammation were specifically excluded from the study. Patient satisfaction was only briefly discussed and not compared to the standard surgery group.

Not mentioned in the paper is the cost of the robot which is at least $1.3 million plus yearly maintenance fees of hundreds of thousands of dollars. All of this is being advocated without any evidence that the robot is safer or more efficacious for any type of surgery, let alone standard laparoscopic cholecystectomy. And it is being promoted to avoid three 5 mm incisions which in most patients are not painful and barely visible if at all.

All I can say is "Klaatu barada nikto," which some have interpreted to mean “This escalation is unnecessary.”

You guys who don't try this and take pot shots really make me laugh. The same statements were made about laparoscopic cholecystectomies 20 years ago. Technologies and instrumentation has evolved and will evolve for robotic surgery as well. This is an early result and should be viewed as such. I predict that single port robotic cholecystectomy will be the rule rater than the exception in the next 5 years.Best of luck,John D. McKenzie, M.D.

John, thanks for commenting. I agree that people scoffed at the original laparoscopic GB concept. But there are differences between that transition and the transition from 4 port to 1 port such as cost and the minimal to no real advantage for patients.

Since I don't speak or read much Spanish, I'll take your word on this.

I realize single-port cholecystectomy can be done. The fact that it can be done does not mean it should be done.

In the December 2012 issue of Surgery, Dr. Nancry Perrier explains why she has abandoned single-incision trans axillary robotic thyroidectomy. Here's a link (http://www.ncbi.nlm.nih.gov/pubmed?term=perrier%20nd) but there's no abstract.

Here is her last paragraph:

"After performing nearly 40 RATS procedures, we came to the conclusion that the main benefit of RATS---translocation of the surgical incision to the axilla---did not offset the risks and liability of performing an operation that was not supported by the equipment manufacturer, took twice as many resources to perform as open surgery, and faces complex legal hurdles beyond our control that currently prevent implementation of telerobotic/ distant access surgery across the United States. Justifying the expense in a time when demands outweigh resources obligated us to focus on outcomes. When we did that, we proved that we could perform RATS, but not that we should."